The present invention relates generally to a method and apparatus for infusing fruit, and more particularly to such a method and apparatus wherein there is a substantial juice byproduct and the fruit does not appear to have been dehydrated during processing, the fruit having the characteristics of juiciness and sweetness.
U.S. Pat. No. 4,626,434, assigned to Rich Products, relates to a single step process for infusing fruit. In this process the fruit is placed into a 70% fructose syrup bath maintained at a temperature of approximately 65-71xc2x0 C. (150-160xc2x0 F.). (It is possible to use sucrose, which is a disaccharide consisting of fructose and glucose chemically bonded together. During processing the sucrose will be xe2x80x9cinvertedxe2x80x9d, i.e., the bond will be shattered and the sucrose will end up as fructose and glucose.) In the sugar syrup bath a portion of the fruit juice (water and aromatics) within the fruit will pass through the outer membranes of the fruit osmotically, and as the water tends to dilute the sugar syrup, the sugar syrup will be maintained at or near its initial sugar percentage by introducing concentrated sugar syrups. During this time equal amounts of diluted syrup are withdrawn and subsequently treated, the final byproduct being a sugar syrup which is reintroduced into the bath. The disadvantage of the Rich Products process is that the water goes out of the fruit faster than the sugar goes in, causing osmotic dehydration of the fruit. Once the fruit is osmotically dehydrated, it cannot be xe2x80x9cplumped up,xe2x80x9d i.e., re-infused with a plumping liquid so that it does not appear to be dehydrated. In addition, there are no juice by-products. The juice is irretrievably mixed with the syrup.
U.S. Pat. No. 5,320,861, assigned to Ocean Spray, discloses a two step process for infusing fruit. In the first step a decharacterized fruit product is produced by a countercurrent xe2x80x9cleachingxe2x80x9d process. In the countercurrent process up to 94% of the fruit juice content is extracted and is replaced by water. This process does not cause osmotic dehydration as the osmotic transfer rates of the water and fruit juices are substantially the same. The decharacterized fruit is substantially nothing more than cellulose and water. The byproduct of this process is 3% fruit juice, which can be changed by evaporation to full strength. The second step of the process also uses a countercurrent process, the apparatus being substantially identical to that used in the first step of the process. During the second step an aqueous blend (or liquor) of sucrose and cranberry fruit juice components (or other equivalent fruit components) is used to infuse the decharacterized fruit. In addition, fruit flavorings and food colorings must be added to the infusing liquor used in the second step of the process in order to make the infused fruit resemble a cranberry. The result is a new fruit product in the way of infused cranberry having the sweetened flavor of the infusing liquor and cranberry juice. The resultant fruit product is dried and optimally has a sugar to water by weight ratio of about 70%. This sugar to water weight ratio is commonly referred to as Brix in the industry, and this term will be used in the remained of this specification. The disadvantage of this process is that the augers used by the countercurrent process is rough on soft or fragile fruit, causing too many undesirable fines. In addition, as water is extracted from the cranberries during the second step, the water will dilute the infusing liquor, and the augers cause mixing of dilute infusing liquor with the initial concentrated infusing liquor.
U.S. Pat. No. 2,785,071 to Mathews teaches infusing previously extracted fruit by moving a sugar front through the previously extracted fruit, the front having a sugar content beginning at zero and increasing in sugar content as the front is passed by the layers of fruit. In order to properly infuse the fruit according to the Mathews patent, a pretreatment process must be followed to prepare the fruit for infusing. The fruit must be soaked in a solution bath of xc2xc to 1% of sulfur dioxide brine. The brine acts as a preservative for the fruit. Next, the fruit is boiled in order to volatilize the sulfur dioxide from the fruit.
Boiling also cooks the fruit, tenderizes the fruit, and loosens the fibrous material. The fruit is next washed, diced, and washed again. The fruit now needs to be dyed in order to have any color. The infusion portion of the process disclosed in Mathews is a sequential batch process and is illustrated best in FIG. 1 of the Mathews patent. In the infusion process tanks 6, 7, and 8 are filled with the fruit to be processed, and a front of sugar heated to 49-60xc2x0 C. (120-140xc2x0 F.) is initially introduced into the base of tank 6, the sugar initially having a high sugar content.
As the front of sugar syrup moves up though tank 6, it will be diluted by the water in the fruit cells of the fruit within the tank in a manner similar to that disclosed in the Rich patent. As the sugar front initially passes through conduit 21 it will have only a slightly higher sugar percentage than that of the fruit through which it has passed. (The initial tank will have fruit which suffers from osmotic dehydration.) As the front of sugar moves up through tank 7 the succeeding fronts of sugar increase in Brix content, and the fruit product will be sweetened. The Mathews patent sweetens the fruit to 77 Brix. A disadvantage of the process is in the pretreatment necessary to prepare it for impregnation with syrup. Thus the fruit is boiled and washed several times, which ruins the flavor of the fruit. In addition, the high temperatures recommended for both pretreatment and infusing turn the fruit mushy and will discolor some fruits, such as cranberries and strawberries. Furthermore, since virtually all the juice of the fruit is washed out during pretreatment, there is no possibility of extracting fruit juice. In addition, this process is not feasible for soft, previously frozen fruit.
U.S. Pat. No. 1,534,050 to Barrielle suggests a method in which fruit contained in a xe2x80x9cplurality of vatsxe2x80x9d (in his example he proposes 20 vats) is brought systematically in contact with a sugar syrup, starting with the most infused vat, proceeding finally to the least infused vat. The weakened syrup is then restored via evaporation and sugar addition to its original strength. It can then be used again. The syrup it said to follow a xe2x80x9ccontinuous and uninterrupted cyclexe2x80x9d. The syrup is admitted either from the top or bottom of each vat, and the suggested temperature is 50xc2x0 C. to 75xc2x0 C. In the Barrielle patent no mention is given as to what is to be done with fruit juice that diffuses out of the fruit during infusion of sugar. He mentions only that xe2x80x9cthe fruits that are in contact with solutions of gradually increasing richness in sugar give off their water by osmosisxe2x80x9d. This would be true if the fruit initially contained only pure water,(i.e. If the juice were previously removed). Perhaps he assumed this would be true. Unfortunately most fruit contains fruit juice, which contains flavor elements, color elements, tannins (bitter elements), natural pectin, odors, and hundreds of other chemical compounds. Many of these natural constituents of fruit juice remain behind during evaporation, thus constantly increasing in strength with each pass through the system. This quickly spoils the syrup which gets very dark and bitter and which turns to a gel due to the presence of pectin. It then must be discarded or sold as a low price item. (It is this very problem that Mantius avoids by washing almost all the juice out with water prior to infusion.)
U.S. Pat. No. 4,232,419 to Limpert teaches that the fruit is pre-treated by sulphur dioxide brine, and several washings with water prior to infusion. No juice extraction is possible.
U.S. Pat. No. 1,717,258 to Rambaud teaches a process of enriching fruit with sugar. There is no mention of juice extraction. The concentrated sugar syrup is introduced from the top of each vessel, and the diluted sugar syrup is also withdrawn from the top of each vessel. This would cause undesirable mixing of the front. No mention is made of how he plans on handling ever increasing volumes of infusion syrup.
It is an object of the present invention to provide a method and apparatus which overcomes the disadvantages of prior processes.
More particularly, it is an object of the present invention to provide a method and apparatus for infusing fruit which will produce an infused fruit having the characteristics of juiciness and sweetness.
A further object of the present invention is to extract juice and infuse sugar into a fruit in one step, while still producing a substantially pure juice product.
It is a further object of the present invention to process fruit to be infused with sugar at temperatures which do not exceed 38xc2x0 C. (100xc2x0 F.), and which preferably may be carried out at temperatures at or below room temperature. By using temperatures which don""t exceed 38xc2x0 C. quick fermentation of the diluted fruit front is avoided.
It is a further object of the present invention to infuse fruit gently with no stirring or agitation, so that soft, fragile and/or previously frozen fruit may be processed.
A still further object of the present invention is to reduce the need for use of evaporators to recycle and reuse infusing liquor.
It is yet a further object of the present invention to infuse fruit without using preservatives and without losing much of the natural aromatics contained within raw fruit.
Another object of the present invention is to provide a method and apparatus for infusing fruits which may be practiced with just one vat or with many vats.
These and other objects and advantages of this invention will be apparent to one having ordinary skill in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings.